Synthesis, structure, spectroscopy and antitumor activity of hydroxy naphthoquinone thiosemicarbazone and its metal complexes against MCF-7 human breast cancer cell line

Coordinately unsaturated metal complexes of the stoichiometry [M(HL)Cl] and [Fe(HL)Cl 2 ].2H 2 O have been isolated (where M=Cu(II), Ni(II), Pd(II) and Pt(II); HL=tridentate anion of H 2 L 3). The X-ray crystal structure for4-hydroxy-3-methyl-1,2-naphthoquinone-1-thiosemicarbazone, 3 has been determined which crystallizes in space group P2 t /c, a = 7.430(3), b = 10.794(3), c = 17.216(5) A, β =92.91(3)°, Z = 4, and have 'E' configuration. The Cu(II) 3a, Ni(II) 3c, Pd(II) 3d and Pt(II) 3e complexes are found to possess square planar geometries, whereas Fe(III) complex 3b possesses a square pyramidal configuration. The in vitro activity of the synthesized compounds examined against human breast cancer cell line MCF-7 clearly indicates that metal complexation enhances antitumor activity, the highest being for the copper complex 3a.